docs(readme): add badges

Author: richardschneider

README.md

@@ -1,2 +1,7 @@
 # net-ipfs-api
+
+[![build status](https://ci.appveyor.com/api/projects/status/github/richardschneider/net-ipfs-api?branch=master&svg=true)](https://ci.appveyor.com/project/richardschneider/net-ipfs-api) 
+[![Coverage Status](https://coveralls.io/repos/richardschneider/net-ipfs-api/badge.svg?branch=master&service=github)](https://coveralls.io/github/richardschneider/net-ipfs-api?branch=master)
+[![Version](https://img.shields.io/nuget/v/Ipfs.Core.svg)](https://www.nuget.org/packages/Ipfs.Core)
+
 InterPlanetary File System API for .Net (C#, VB, F# ...)